Kinematic methods will be used to study normal speech breathing across the human life span in both cross-sectional and longitudinal research designs. Specific aims of the research are to determine how speech breathing emerges in the infant, how it is refined in the child and adolescent, and howe it is modified in the adult. Major variables to be considered include gender, age, somatotype, and body position. Primary observation methods will involve the use of magnetometer and Respitrace systems. Major analysis methods will involve graphic displays of rib cage volume and abdominal volume from which measurements will be made and inferences drawn concerning underlying muscular mechanisms. Data provided will enable the first description of the natural course of changes in speech breathing across the life span and will provide normative information of use as a standard for clinical evaluation and management of speech disorders with respiratory bases. Foremost relevance of the research to clinical endeavors should be in relation to those disorders caused by neuromotor dysfunction, including cerebral palsy, spinal cord injury, poliomyelitis, myasthenia gravis, spinal muscular atrophy, peripheral neuropathy, muscular dystrophy, and others.